Originally Posted by Grimaldi.org, the official site of the House of Grimaldi.

In the 15th century, John Grimaldi, lord of Monaco, formally established in his will (1454) the Rules of Succession. It was an important step since Monaco had been a condominium until then.

The rule can be summarized as follows: First in line of succession is the male issue, whether legitimate or not, by primogeniture. In the absence of a male heir enters the female issue, whether legitimate or not, by primogeniture, provided that the candidate marries a man legitimately born of the Grimaldi lineage — "unum hominem seu virum natum legitime de progenie seu albergo Grimaldorum."

Otherwise, the succession passes to the most closely related member of the Grimaldi albergo. In case there would be two or more Grimaldi cousins alive at equal degrees, the eldest would be chosen.

According to this Fundamental Law, Alexandre, the eldest son of Prince Albert II of Monaco, is the apparent heir of the Monegasque throne.

In Monaco, the natural children were never excluded from the inheritance order. Prince's Rainier III mother, Princess Charlotte, the princely origin of all current Grimaldi, was herself a natural child.

Prince Rainier III, was not authorized to modify this Fundamental Law, as he did in 2002.

Actually, according to the Rules of Succession laid by Lord Giovanni I in 1454, as you correctly state, NONE of the current members of the ruling family of Monaco have a right to this honour and power. When Prince-Archibishop Honore-Francois died in 1748, the Monaco succession should have passed by rights to his cousin Sauvier-Gaspard Grimaldi, Marquis of Antibes, and when his line died out in 1940, to Fernand Grimaldi, Count of Puget, and should today be held by his ageing son, war veteran Jean Grimadi de Puget, with his heir being his eldest son Henri Grimaldi de Puget. Of course this situation could always be rectified by the reigning Prince Albert Grimaldi-Polignac marrying his daughter to a son of Henri, or one of his male Grimaldi relatives- there are quite a number of these. This spouse would then succeed toegethr with his wief as Prince and Princess of Monaco, and their children continue the line. While prince Rainier's constitution ignores this, it cannot be overlooked that without the original Grimaldis, the Principality of Monaco would never have existed, therefore the 1454 Rules of Succession should be incorporated into the modern constitution.